Prev property mgmt company charging to release prorated rent

To be honest with you I thought I had gotten the prorated amount of rent for August when we closed on 8/14/15, but this wasn't the case.  Being that this is my first deal I probably should have paid a little bit closer attention.  Ever since I told the old property management company that I wouldn't be retaining their services they've become a pain in the butt.  I still haven't gotten the security deposits back from them and I just got keys earlier this week.  Then their manager sends me this email today. 

"I ran into a small problem with printing your check. The two prorated rent checks I have for you total more than $600 ($657.22) – my system won’t print the checks without a W-9 on file then at the end of the year we will send you a 1099. Our fee for processing the 1099 to the owners at the end of the year is $75. I can write you a check for $599, thus eliminating the need for the W-9 and 1099 at the end of the year, or you can fill out a W-9 form and I can write the check to you, less our processing fee."

I wrote her back telling her that her figure seemed off to me.  The rents they collected for August were $1415.  Divided by 31 that's about $45.65 per day which means I should be receiving about $821 because I owned the property for 18 days in August.  I asked her to share her math with me, we'll see what she says.

Now on to the part about my question.  Can she really force me to fill out a 1099 for her company and charge me $75?  This seems ludicrous to me.  This is in Michigan.